Willful vs. Wilful
“Willful” and “wilful” are regional spelling variants of the same adjective. Cambridge identifies “willful” as the US spelling of “wilful.”
Use “willful” in US English and “wilful” in UK-oriented English, unless your house style specifies otherwise.
Key details
Choose the right form
| Audience / style | Use | Meaning |
|---|---|---|
| US English | willful | US spelling. |
| UK-oriented English | wilful | UK spelling. |
| Legal / institutional wording | follow governing text | Fixed statutory or organizational wording should be preserved. |
Quick tests
Style test
Does the document follow US or UK spelling, or quote a governing legal/institutional form?
If yes: Use the required regional or governing spelling.
If no: If no style is fixed, choose one documented form and stay consistent.
Caveat: The spelling difference does not by itself create a difference in meaning.
Examples
US style: The policy addresses willful misconduct.
“Willful” is the documented US spelling.
UK style: The policy addresses wilful misconduct.
“Wilful” is the documented UK spelling.
Further guidance
Core difference
“Willful” and “wilful” are regional spellings of the same adjective.
Usage Boundary
Use “willful” in US English and “wilful” in UK-oriented English unless a house style requires another convention.
Sources and evidence
Sources are shown with the role they play in this guide. Historical or style-sensitive claims are kept within the evidence boundary described above.
- Willful — Cambridge Dictionary (opens in a new tab)Cambridge University Press · Direct evidence identifying willful as the US spelling of wilful.